The present invention relates to a service life sensor device for determining the material stress in machine-technical installations, and in particular, a service life sensor device including a sensor module for detecting tensions and expansions in structural components of these installations to thereby determine the serviceable life of the installation.
The prognosis of the serviceable life of machine-technical installations and structural components thereof is highly important, especially as it relates to those installations that are built to tolerate vibrations and that are under long periods of operation and are therefore prone to fatigue. Thus, determination of the service life is very important for securing continued flawless operation of the installation and their components and to avoid and prevent damage to the installation.
In this context, it is known in the prior art to attach sensors to machine-technical components in order to determine strain or damage to the part and to determine its upper limit load amount.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
The known sensors consist in general of expansion measuring strips, which must be fastened to the installation component and which must be coupled to a sorting-/evaluation unit and to electric current. However, the cabling lay-out of these units is generally impractical and feasible in only few applications to monitor the structural building components and such measuring operations are very labor-intensive. In addition, measuring units of this type take up an inordinate amount of space due to their complexity in supplying necessary electric current, providing data interpretation units and measuring sensors, such that taking continuous measurements with these monitoring devices are only feasible in a limited number of applications due to the afore-stated constraints. Therefore, utilization of this type of sensors is generally associated with high expenses and considered impractical in their operation.
The prior art as disclosed in U.S. Pat. No. 5,421,204 includes a method and device for determining the useful life of technical structures that are subject to fatigue, or buildings such as bridges and similar. This prior art device comprises a sensor which includes expansion measuring strips for collecting data on the tensions and expansions in the structural parts as well as a data storage, a control device and a data interpretation unit, a transmitter, a receiver, an antenna arrangement and a battery as a current source. These components are assembled into a unit for placement in a fixed position at the installation component to be monitored. From the collected data of the measured expansions and tensions and the determination of the stress loads by means of applicable calculating methods, a computation of the damage to the installation can be realized.
The foregoing method of measuring, collecting and determining data is however cumbersome and since the device is operated based on batteries, its operational readiness is dependent on the capacity of the battery.
It would therefore be desirable and advantageous to obviate prior art shortcomings and to provide an improved device for determining the serviceable life of machine-technical installations.